On demand water heater installation

[jlegere]

does anyone know of a device that will turn off one circuit when another is turned on? I would like to disable my a/c when the on demand water heater is turned on. this will keep me from popping breakers when the water heater kicks on.

[AmericaOverland]

It appears you need higher amperage than is designed for RVs in order for on-demand water heaters to work well in shower environments. I really wanted to look into this, considering that I'm a woman with long hair. I just have to shower twice, once for my hair, and second for my body. Fortunately, given my farm lifestyle, I only do the former about twice a week and the latter every day, just a five-minute rinse down to warm up or cool down, depending on the time of the year.

[Chris_Bryant]

I do not believe an electric on demand water heater is practical in an RV, unless it is a 50 amp rig, and you don't mind spending more than half of that capacity on hot water. Most I have seen are 30 amp/240 volt units- 20 amps at 120 volts just is not going to heat water on demand very well.

Looking- a 3400 watt 120 volt model only gives a 35 degree rise at .7 gpm- not enough for a shower to me, just enough for hand washing.

[rv2go]

jlegere wrote:
not exactly sure but the device that will take priority will be an on demand electric water heater. the secondary will be the a/c unit so a 20 will take care of that side.

It's really hard to help not knowing what you need amp wise.

[jlegere]

not exactly sure but the device that will take priority will be an on demand electric water heater. the secondary will be the a/c unit so a 20 will take care of that side.

[rv2go]

jlegere wrote:
that is exactly what is needed, but in higher amperages.

What amperage are you trying to shift? They make the same device in 30 Amp.

[jlegere]

that is exactly what is needed, but in higher amperages.

[rv2go]

I think what you need is a 20 Amp Automatic Load Shed Device. You just set the one that you want to be priority. Some RV's have an Engery Manage System that does the same.

[camperpaul]

A 20 Amp SPDT (3 Way) switch will do the job for you.

Not high tech and cheap (under $10.00 for parts).